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yes I understand now, for the primer on my smps to reach 350v, if to divide a smaller voltage, for example 150v, does the dividing resistor have to be adjusted too?
with the scope specifications I have, with a max input of 40v peak, is it safe for Silvio, ??

what if using a 2x47k (2 watts) 10k (2watt), is that not a problem in reading

The wattage in the resistors is there so that they do not burn with the voltage applied to them. If you have larger watt resistors its no problem.

This is how I worked it. There is around 350v volts at the primary so first we work out the current with ohms law

V= I x R so V/R =I so 350v / 100000 ohms = 0.0035A or 3.5mA

W = V x I so 350v x 0.0035A = 1.225W

You have to choose a larger watt resistor than 1.2W because it will heat up a lot however I divided the resistor of 100k with 2 x 47k so that the power will be divided. However most of the voltage drop will be in the 47K resistors. The 10K resistor will not have a lot of voltage drop in it so 1watt will be enough.